# io.github.lukasschwarz/elster-mcp-server (npm · elster-mcp-server)

Drive the German tax portal ELSTER via Puppeteer: submit UStVA, prepare EUER/ESt, sync inbox.

- Trust score: 53/100 (low)
- Change this week: +10
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

- npm · `elster-mcp-server`: 53/100 (this document), [markdown](https://verifymcp.io/servers/lukasschwarz-elster-mcp-server/elster-mcp-server.md), [page](https://verifymcp.io/servers/lukasschwarz-elster-mcp-server/elster-mcp-server)

## Channel facts

- Registry: `npm`
- Package: `elster-mcp-server`
- Version: `0.1.0`
- Transport: `stdio`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-08-03.

- **Supply Chain Security**: 70/100
  - No malware found by supply-chain analysis.
  - CVE check failed: a known high-severity CVE affects @modelcontextprotocol/sdk 0.6.1, a direct dependency. A fixed version is available.
  - No install/post-install scripts declared.
  - Only part of the dependency tree could be resolved (115 of 116), so this covers what we could see, not the whole tree.
- **Provenance & Transparency**: 45/100
  - Source repository is publicly reachable at the declared URL.
  - Provenance check failed: no build-provenance attestation is published.
  - Clear OSI-approved license (MIT).
  - Actively maintained (last published 36 days ago).
  - Disclosure check failed: no security disclosure policy was found in the source repository.
- **Schema Quality & AI Usability**: 71/100
  - AI-judged instruction clarity (good).
  - Tool/resource definitions use about 1020 tokens (~72/item across 14 items; 14 tools + 0 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 0/100
  - Stability not yet verified: not enough scan history yet (needs a 30-day window).
- **Tool Coverage**: 79/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 37% of tool parameters carry a description.
- **Capabilities**: 20/100
  - Spec-recency check failed: implements MCP spec 2024-11-05; the latest is 2026-07-28.

**Unverified: 1 category.** A category scored 0 because we could not verify it: a data source with nothing on this package, evidence we could not reach, or a check we could not run. We only credit what we can confirm.

## Install

### Claude

```bash
claude mcp add lukasschwarz-elster-mcp-server -- npx -y elster-mcp-server
```

### Codex

```bash
codex mcp add lukasschwarz-elster-mcp-server -- npx -y elster-mcp-server
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "lukasschwarz-elster-mcp-server": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "elster-mcp-server"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add lukasschwarz-elster-mcp-server --command npx --arg -y --arg elster-mcp-server
```

### Hermes

```yaml
mcp_servers:
  lukasschwarz-elster-mcp-server:
    command: "npx"
    args: ["-y", "elster-mcp-server"]
```

### Other

```json
{
  "mcpServers": {
    "lukasschwarz-elster-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "elster-mcp-server"
      ]
    }
  }
}
```

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-08-02 (score 53, +34)

- [security regression] CVE-2025-66414 affects this package: high
- [security regression] Provenance: unverified → fail
- [security regression] Known CVEs: unverified → fail
- [security improvement] Install scripts: unverified → pass
- [security improvement] Malware scan: unverified → pass
- [security] Stability: Stability not yet verified: not enough scan history yet (needs a 30-day window).
- [functional regression] MCP protocol: unverified → fail
- [functional regression] Tool coverage: 100 → unverified
- [functional improvement] License: unverified → pass
- [functional improvement] Dependency health: unverified → partial
- [functional improvement] Maintenance: unverified → pass
- [functional improvement] Schema quality: unverified → good
- [functional] First check of Schema quality: unverified
- [functional] Licence: MIT

### 2026-07-31 (score 19, −24)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-27 (score 43)

First indexed and scored.

## MCP tools (14)

### `elster_login_test` (~42 tokens)

Verifies that the configured certificate + password can log into the ELSTER portal. Returns success and final URL or an error. Use this once before submitting anything.

### `elster_config_show` (~36 tokens)

Shows the currently loaded ELSTER configuration (with secrets redacted) so you can verify env vars / config.json were picked up.

### `elster_kennziffern_list` (~55 tokens)

Returns the list of supported UStVA Kennziffern (codes 81, 86, 66 etc.) with descriptions and whether they are NET (base amount) or TAX (tax amount).

### `elster_ustva_generate_xml` (~135 tokens)

Generates an ELSTER UStVA XML snapshot for archiving. Does NOT submit (submission goes via elster_ustva_start). Useful for audit trails.

Input parameters:

- `period` (integer|string, required): Month (1-12) or quarter as "Q1".."Q4"
- `report` (object, required): Map of Kennziffer → amount in EUR. Keys are the bare 2-3 digit code (e.g. "81", "66"). Net amounts for NET-type codes, tax amounts for TAX-type codes.
- `year` (integer, required): Tax year, e.g. 2026

### `elster_ustva_detect_reverse_charge` (~69 tokens)

Tests whether a voucher would be detected as Reverse-Charge (§13b UStG) based on the configured supplier patterns. Returns matched supplier and region (EU / NON_EU), or null.

Input parameters:

- `contactName` (string)
- `description` (string)

### `elster_ustva_start` (~129 tokens)

Starts a UStVA submission session. Opens a browser, logs in, fills the form, runs Prüfung, then PAUSES at AWAITING_CONFIRM. You must explicitly call elster_ustva_confirm to send. Returns a sessionId — poll status via elster_session_status.

Input parameters:

- `period` (integer|string, required): Month (1-12) or "Q1".."Q4"
- `report` (object, required): Map of Kennziffer → amount in EUR (bare digit keys, e.g. "81":12345.67).
- `year` (integer, required)

### `elster_ustva_confirm` (~55 tokens)

Confirms submission of a UStVA session that is in AWAITING_CONFIRM state. Triggers the final "Absenden" click. Returns the transmission ticket on success.

Input parameters:

- `sessionId` (string, required)

### `elster_eur_start` (~168 tokens)

Starts an EÜR (Anlage Einnahmen-Überschuss-Rechnung) form-prep session. Fills the form up to Prüfung, then tries to "Speichern und Verlassen" so the draft survives in ELSTER. NEVER submits.

Input parameters:

- `data` (object, required): Map of field names to numeric amounts. Supported fields: betriebseinnahmen, kfzPrivatNutzung, fahrzeugkosten, kfzSteuer, telekommunikation, versicherungen, bewirtung, reisekosten, bankgebuehren, frem…
- `year` (integer, required)

### `elster_est_start` (~119 tokens)

Starts an ESt 1 A (Einkommensteuererklärung) form-prep session. Opens the form, fills taxpayer basics from config + any extra fields you provide (by ELSTER input id/name hint), runs Prüfung, then waits 30 min for you to review in the portal. NEVER submits.

Input parameters:

- `data` (object): Optional map of field-id hints → values. Each key is matched against ELSTER input id/name as substring. Use empty {} to only fill taxpayer basics from config.
- `year` (integer, required)

### `elster_session_status` (~53 tokens)

Returns the current status, progress log, and any screenshot path for a session started via elster_ustva_start / elster_eur_start / elster_est_start.

Input parameters:

- `sessionId` (string, required)

### `elster_session_list` (~30 tokens)

Lists all currently tracked sessions (USTVA / EUR / EST / SYNC) with their status.

### `elster_session_cancel` (~35 tokens)

Cancels a running session (closes the browser, marks status as CANCELLED).

Input parameters:

- `sessionId` (string, required)

### `elster_sync_history` (~48 tokens)

Reads "Übermittelte Formulare" (transmission history) from ELSTER. Optionally downloads PDFs.

Input parameters:

- `downloadPdfs` (boolean)
- `years` (array)

### `elster_sync_inbox` (~46 tokens)

Reads ELSTER inbox messages ("Posteingang"). Optionally downloads each message as PDF.

Input parameters:

- `downloadPdfs` (boolean)
- `maxPages` (integer)

## Diagnostics

Captured diagnostic sections: Provenance, Vulnerabilities, Dependencies. The full working is on the page: https://verifymcp.io/servers/lukasschwarz-elster-mcp-server/elster-mcp-server#diagnostics

## Score history

- 2026-08-03: 53
- 2026-08-02: 53
- 2026-08-01: 19
- 2026-07-31: 19
- 2026-07-30: 43
- 2026-07-28: 43
- 2026-07-27: 43

## Links

- npm package: https://www.npmjs.com/package/elster-mcp-server
- Socket report: https://socket.dev/npm/package/elster-mcp-server
- Repository: https://github.com/lukasschwarz/elster-mcp-server
- Changelog RSS feed: https://verifymcp.io/servers/lukasschwarz-elster-mcp-server/elster-mcp-server/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/lukasschwarz-elster-mcp-server/elster-mcp-server/changelog.json
- HTML version of this page: https://verifymcp.io/servers/lukasschwarz-elster-mcp-server/elster-mcp-server